Absorption refrigeration



Patented Dec. 19 i950 .UNITED STATES PATENT .orrlcs ABSORPTION REFRIGERATION Glen W. Miller, Covina, Edward L. Kells, Alhambra, and-Delmar H. Larsen, West Hollywood,

Calif.

N Drawing.

' v 12 Claims.

invention relates to improvements in absorption 'refrigeration, fand more particularly to new and useful refrigerant-solvent combinations 1 for. use in absorption refrigeration. This applica- Another object of the invention is to provide an absorption refrigeration solvent of high density.

Other objects of the invention will become apparent as the description thereof proceeds.

In absorption refrigeration systems, the refrigerating effect is produced by the evaporation of a liquid refrigerant by allowing it to expand from a pressure greater than its vapor pressure at cooling water temperature to a pressure less than its vapor pressure at the refrigerating temperature. In order to re-cycle the refrigerant, it is absorbed into a liquid of high solvent power; thus dissolved, it is pumped to the higher pressure and driven from the solvent by heat. The function of the solvent is thus to reduce to a minimum the mechanical work necessary in bridging the low'and high pressure sides of this system, since the volume of the refrigerant ,as pumped is reduced. The remainderof the necessary energy used to drive the refrigerant from this solution can then Application October 5, 1948, Serial N0. 701,402

detail in various books on refrigeration engineerin An improved method of operation of such systems, employing fractionation of refrigerant and 5 solvent, is disclosed inour hereinabove cited Patent No. 2,408,802, and while the refrigerant-solvent combinations of this invention can be used in a machine embodying this method, it should be understood that the refrigerant-solvent com- 10 binations described and claimed hereinmay also be used in conventional machines of types already in use, in some cases with slight mechanical adjustments to meet changed operating conditions, as will be apparent to oneskilled in the art of 15 refrigeration engineering. Such machines include types having externally operated pumps for effecting transfer of the fluids contained therein, as well as those types depending upon pressures balanced out by means of an inert gas, flow being inducedby differences in specific gravity of the fluids in different parts of the system.

In accordance with the present invention, perchloroethylene (C2014; 1,1,2,2 tetrachloroethylene) is used as a solvent, in one of four combinations C2CI2F4, dichlorotetrafluoro- (b). (c) (d) The following table gives for each such combination the refrigerant boiling point, the solvent boiling point (both at one atmosphere), the difference in these boiling points, the maximum boiler temperature for a 100 F. condenser temperature, and the theoretical minimum energy ratio (ratio of total heat input to total useful refrigbe supplied by heat. Such systems are, of course, 40 crating effect, both in heat units, allowing a 20% well-known and may be found described in full stack loss-in heat input to boiler):

(Table-1 i .Reil'ig. Solvent Difler- Mari. Boiler Refrigerant Solvent ,3. an n. P. once in Temp. for g j 1st 1 atm. B. P. 100 F. oond.

, '6 F. F. F.

Freon 114 (CiChFi) Perchloroethylene (C1014)... '42 276 234 385 1.95

Freon 21 (CHClzF) 48 276 228 370 l.

Further in accordance with the invention it is contemplated that other halogenated hydrocar- .bons besides those given above can be used as Table 2 P Name Formula 1 ntm.,

Dichlorodifiuoromethnne; Freon 12 2l. 7 Methyl chloride CH C 1 -ll Chlurotriiluorometbane CC 1 112 Chlorodifiuoromethanc" -41 Fluorolorm -116 Dlfluoromethane.-- -60 Methyl fluoride --l09 Chloropentailuoroetlmne 3G l,l-dicbloro-l.2,2,2 tetrslluoroethane +28 l,2-dlchloro-l,l,2,2 tetrailuorocthane +39 Perfiuoroetbune.-- -1l0 1,1 dichloroethylcne. +99 1,1,l-trifluoroethsne. 52 1,1 diiluoroethane. l3 1,2 diiiuoroethsne +51 Ethyl fluoride C2H5F .1 -36 Propenyl chloride ;H C1 +96 lsopro-{ienyl chloride .do 1 +73 Allyl uoridc +14 2,2-difluorometbune. +31 Isopropyl fluoridc.. +14 Propyl fluoride +27 I At 738 mm. Hg.

Perchloroethylene is of great functional usefulness as a solvent because of its chemical stability, inertness towards metals, high density (which results in small volumes of solvent to be pumped and easy separation of the liquid droplets from L the vapor in the analyzer) and particularly because of its high solvent power for the refrigerants listed in Table l, and for the refrigerants listed in Table 2, and for the general class of refrigerants exemplified by Tables 1 and 2. It is cheap and readily available in a quite pure form.

Fluorochloro derivatives of simple aliphatic hydrocarbons and of boiling points similar to that of perchloroethylene have been suggested as absorption refrigeration solvents. However, they suffer from lower density and much higher cost.

It should be noted that in the case of the refrigerants of very low boiling point, high boilerside pressures will be needed to effect liquefacconcentration as the solvent and a refrigerant in substantial concentration chosen from the group of aliphatic hydrocarbons of fewer than four carbon atoms and having at least one hydrogen atom substituted by a halogen of atomic weight less than 50.

2. A refrigerant-solvent combination for use in absorption refrigeration machines consisting essentially of perchloroethylene insubstantial concentration as the solvent and a refrigerant in sub-- stantial concentration chosen from the group of aliphatic hydrocarbons of fewer than four carbon atoms and having at least one hydrogen atom substituted by a halogen of atomic weight less than and having a boiling point between the approximate limits of -1l6 F. and 99 F.

3. A refrigerant-solvent combination for use in absorption refrigeration machines consisting essentially of perchloroethylene in substantial concentration as the solvent and the dichlorotetrafluoroethane (Freon 114) in substantial concentration as the refrigerant.

a. A refrigerant-solvent combination for use in absorption refrigeration machines consisting essentially of perchloroethylene in substantial concentration as the solvent and dichlorofiuoromethane (Freon 2-1) in substantial concentration as the refrigerant.

5. A refrigerant-solvent combination for use in absorption refrigeration machines consisting essentially of perchloroethylene in substantial concentration as the solvent and trichlorofiuoromethane (Freon 11) in substantial concentration as the refrigerant.

6. A refrigerant-solvent combination for use in absorption refrigeration machines consisting essentially of perchloroethylene in substantial concentration as the solvent and ethyl chloride in substantial concentration as the refrigerant.

'7. The process of absorption refrigeration comprising circulating a refrigerant chosen from the group of lower aliphatic hydrocarbons having at least one hydrogen atom substituted by a halogen of atomic weight less than 50 through an evaporator and to an absorber, absorbing the vaporized refrigerant in a solvent consisting essentially of perchloroethylene, transferring the solution to a still, and therein separating the refrigerant from the solvent.

8. The process according to claim 7 wherein 'the refrigerant has a boiling point between the approximate limits of -118 F. and 99 F.

9. The process according to claim '7 wherein the refrigerant is dichlorotetraiiuoroethane (Freon 114).

19. The process according to claim '7 wherein the refrigerant is dichlorofiuoromethane (Freon 21).

11. The process according to claim 7 wherein the refrigerant is trichlorofluoromethane (Freon ll) 12. The process according to claim '7 wherein the refrigerant is ethyl chloride.

GLEN W. MILLER. EDWARD L. KELLS. DELMAR H. LARSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,120,559 Jennings June 14, 1938 2,163,899 Walker et al June 2'7, 1939 2,255,584 Hubacker Sept. 9,1941

OTHER REFERENCES Gregory: Uses and Applications of Chemicals and Related Materials, vol. I, Reinhold Publishing Corp., N. Y. C. (1939), page 450. 

1. A REFRIGERANT-SOLVENT COMBINATION FOR USE IN ABSORPTION REFRIGERATION MACHINES CONSISTING ESSENTIALLY OF PERCHLORETHYLENE IN SUBSTANTIAL CONCENTRATION AS THE SOLVENT AND A REFRIGERANT IN SUBSTANTIAL CONCENTRATION CHOSEN FROM THE GROUP OF ALIPHATIC HYDROCARBONS OF FEWER THAN FOUR CARBON ATOMS AND HAVING AT LEAST ONE HYDROGEN ATOM SUBSTITUTED BY A HALOGEN OF ATOMIC WEIGHT LESS THAN
 50. 